Pneumatically powered fastener-driving tool

ABSTRACT

A pneumatically powered fastener-driving tool is provided which incorporates on the housing thereof a removable cap having adjustable means, which when in one position of adjustment will cause the drive piston to make at least one complete cycle when a trigger valve is actuated. When the means is in a second position of adjustment and the trigger valve remains depressed, the drive piston will automatically continue to recycle.

United States Patent El Guindy PNEUMATICALLY POWERED FASTENER-DRIVING TOOL [75] Inventor: Samir E1 Guindy, Mt. Prospect, [11.

[73] Assignee: Spotnails, Inc., Rolling Meadows,

Ill.

[22'] Filed: Aug. 16, 1973 [21] Appl. No.: 388,730

[52] US. Cl. 91/308; 91/309; 91/311; 91/356 [51] Int. Cl. F0ll 25/06; F15b 11/15 [58] Field of Search 91/308, 309, 311, 356

[56] References Cited UNITED STATES PATENTS 3,547,003 12/1970 Ramspeck 91/309 26' 25 all) f 25 a Y 1%? l/ 3,561,324 2/1971 Obergfell 91/309 Primary Examiner-Paul E. Maslousky [57] ABSTRACT A pneumatically powered fastener-driving tool is provided which incorporates on the housing thereof a removable cap having adjustable means, which when in one position of adjustment will cause the drive piston to make at least one complete cycle when a trigger valve is actuated. When the means is in a second position of adjustment and the trigger valve remains depressed, the dr'ive piston will automatically continue to recycle.

8 Claims, 13 Drawing Figures PATENTEDJULZZ I975 3,895, 562

SHEET 2 5 V 5 5 35 A j b g: A! Q Q 1 FIG 5 250" --5 3/1: 60

21 72 FIG. ll

67 u 6/0 7A x 68 g a/ Q) #0 o as &

PNEUMATICALLY POWERED FASTENER-DRIVING TOOL BACKGROUND OF THE INVENTION Various pneumatically powered fastener-driving tools having such capabilities have heretofore been developed; however, because of certain design characteristics, they have been beset with one or more of the following shortcomings: (a) the tool was of complex and costly construction; (b) the mechanism for attaining such capabilities required substantial redesigning of various components comprising the tool and an inordinate amount of maintenance was required to keep the tool in proper running order; (c) the tool was bulky and awkward to handle, and (d) the operation of the tool was inefficient and required an excessive amount of pressured air.

SUMMARY OF THE INVENTION Thus. it is an object of the invention to provide a pneumatically powered fastener-driving tool of the type described which is not beset with the aforenoted shortcomings.

It is a further object of the invention to provide a pneumatically powered fastener-driving tool wherein the mechanism thereof for enabling the drive piston to make a single cycle or repetitive cycles upon depressing of the trigger valve is incorporated within a compact cap which is removably mounted on the tool housing.

It is a still further object of the invention to provide a cap of the type described which may be utilized on an existing non-automatic recycling tool and thereby convert the operation of said tool into an automatic recycling type.

It is a still further object of the invention to provide a tool with a single porting which functions as an exhaust for the cylinder and as an actuating means for effecting automatic repetitive cycling of the drive piston when the trigger valve is maintained in a manually depressed condition.

It is a still further object of the invention to provide a tool which can be operated effectively with a lesser amount of pressured air.

It is a still further object of the invention to provide a tool having a removable cap therefor which incorporates means for controlling the operational speed of the tool.

Further and additional objects will appear from the description, accompanying drawings and appended claims.

In accordance with one embodiment of the invention, a pneumatically powered fastener-driving tool is provided which includes a housing charged with pressured air, a cylinder mounted within the housing, and a reciprocating drive piston disposed within the cylinder and movable between extended and retracted positions. Positioned at one end of the cylinder is a first valve means which is adapted to assume either an open or closed position. When the first valve means is in an open position, pressured air from the housing enters the upper part of the cylinder interior causing the drive piston to move from a retracted position to an extended position. A trigger-type second valve means is mounted on the housing and controls the movement of the first valve means. Removably mounted on the housing adjacent the cylinder one end is a cap provided with adjustable first means which cooperates with said first and second valve means to effect at least one complete cycle of movement of said drive piston upon the second valve means being manually actuated. The cap also includes a second means which cooperates with the first and second valve means and the cap first means to effect repetitive cycling of the drive piston provided the second valve means is retained in a manually actuated condition.

DESCRIPTION For a more complete understanding of the invention, reference should be made to the drawings wherein:

FIG. 1 is a perspective side view of one form of the improved fastener-driving tool;

FIG. 2 is a fragmentary perspective view of the opposite side of the tool of FIG. 1;

FIG. 3 is a perspective view of the tool of FIG. 1 with the cap thereof removed;

FIG. 4 is a perspective view of the cap per se utilized in the tool of FIG. 1 but showing said cap in an inverted position;

FIG. 5 is an enlarged fragmentary sectional view taken along line 5-5 of FIG. 1 and showing the drive piston in a fully retracted position;

FIG. 6 is an enlarged fragmentary sectional view taken along line 66 of FIG. 5;

FIG. 7 is an enlarged fragmentary sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is similar to FIG. 6 but showing the tool cap means adjusted to effect automatic repetitive cycling of the drive piston provided the trigger valve is retained in its manually actuated condition;

FIG. 9 is like FIG. 7 but showing the first valve means in a fully open position.

FIG. 10 is like FIG. 6 but showing the tool cap adjusted so that the drive piston will make only one complete cycle upon the trigger valve being manually actuated;

FIG. 11 is a longitudinal sectional view of the plunger per se carried within the cap for controlling the movement of the drive piston to either one complete cycle or repetitive cycles upon the trigger valve being manually actuated;

FIG. 12 is an enlarged fragmentary sectional view taken along line 1212 of FIG. 10 and showing the tool adjusted for minimum speed; and

FIG. 13 is similar to FIG. 12 but showing the tool adjusted for maximum speed.

Referring now to the drawings and more particularly to FIGS. 1 and 5, one form of a hand-portable pneumatically-powered tool 20 is shown which is adapted to be connected by a suitable length of hose to a source of pressured air, not shown. The tool 20 comprises a housing 21, normally a single casting of a suitable metal or the like, a cylinder 22 disposed within said housing, see FIG. 5, and a reciprocating pneumatically responsive drive piston 23 mounted within the cylinder. The interior of the housing is charged with pressured air. The housing 21 in the illustrated embodiment includes a hollow handle section 21a and a head section 21b. It is the head section in which the cylinder 22 is located. The handle section 21a is charged with pressured air through the hose connector 24 affixed to the rear end of the section. The interiors of the sections 21a and 21b are in continuous communication with one another, as seen in FIG. 5. Overlying the upper end of the cylinder 22 is a poppet-type valve 25 which is adjustable to assume either a closed position A (see FIG. 5), or an open position B (see FIG. 9). When the valve is in its open position B, the pressured air within the interior of the housing section 21b enters the upper end of the cylinder interior and impinges upon the top of the drive piston 23 causing the latter to move downwardly through its drive stroke.

Removably mounted on the upper end of the head section 21b is a cap 26 which is of unitary construction. A suitable gasket 27 is positioned between the head section and the cap and the latter is secured to the head section by a plurality of threaded fasteners 28 which extend into internally threaded openings 30 formed in the upper end of the section 21b, see FIG. 3.

The cap is provided with a first cavity 31 in which is slidably mounted the poppet valve 25. Centrally disposed and extending upwardly from cavity 31 is a cylindrically-shaped portion 31a which is adapted to slidably receive an upwardly extending tubular portion 25a forming a part of the poppet valve. The poppet valve 25 is biased to assume the closed position A by a coil spring 32 which encompasses tubular portion 25a. The spring has one end thereof engaging the upper surface of the cavity 31 and the other end engaging the top of valve 25. A suitable O ring seal 33 is carried by the periphery of the valve 25 and is adapted to slidably and sealingly engage the wall of cavity 31 during movement of the valve, see FIGS. 7 and 9. A similar seal 34 is carried by the valve tubular portion 25a and is'adapted to slidably and sealingly engage the wall of cavity portion 31a.

It will be noted in FIGS. 7 and 9 that the diameter of valve 25 is larger than the outside diameter of the cylinder 22 thereby resulting in the underside of a peripheral portion 25b of the valve being exposed to the charge of pressured air contained within the housing head section 21b.

As seen in FIG. 5, the upper end of cavity portion 31a has extending transversely therefrom an exhaust passageway 35. Communication between cavity portion 31a and the passageway 35 is interrupted by valve tubular portion 25a when the valve 25 assumes its open position B, see FIG. 9. Affixed to the upper end of cavity portion 31a is a seal piece 36 which is adapted to be sealingly engaged by the upper end of the tubular portion 25a when valve 25 is in its fully opened position B, see FIG. 9.

Formed in the cap 26 and spaced from cavity portion 31a is an elongated, transversely extending second cavity 37 having at least one end thereof open. Disposed in snug fit relation within cavity 37 is a sleeve 38 provided with a central bore 40, see FIG. 6. The left end portion a of the bore, as viewed in FIG. 6, has a greater interior diameter than the remainder or righthand portion 40b of the bore. Slidably disposed within the sleeve bore 40 is an elongated rodlike member or spool valve 41.

The right-hand end 38a of sleeve 38 is snuggly fit within the open end 37a of cavity 37 and thus, closes same. The exposed side of end 38a is provided with a threaded hole 38b which is adapted to receive a threaded end of a tool when the sleeve is to be removed from the cavity. A snap ring 39 is placed within a suitable groove formed in the open end of the cavity and thus, retains the sleeve within the cavity. A cross slot 38c is formed in the exposed end of the sleeve so as to enable the sleeve to be rotated within the cavity 37 and thereby vary the operational speed of the tool, see FIGS. 12 and 13, as will be discussed more fully hereinafter.

Spaced longitudinally along cavity 37 are a plurality of ports 42, 43, 44, 45 and 46, see FIGS. 6, 8 and 10. Port 42 is in communication with the bore portion 40a through a suitable opening 38d formed in the sleeve 38, see FIG. 13. Port 42 is connected by a passageway 47 to a central opening 36a formed in seal piece 36, see FIG. 7. Opening 36a is aligned with a bore 250 formed in the valve tubular portion 25a, when the valve 25 is in its fully open position B, see FIG. 9. The bore 1250 extends axially through the valve; thus, when the valve is in position B, the passageway 47 is charged with the pressured air contained within the upper portion of the cylinder in a manner as will be described more fully hereinafter. When valve 25 is in its closed position A, FIG. 7, the exhaust passageway 35 is uncovered by the tubular portion of the valve thus causing passageways 35 and 47 to be in communication with one another.

Port 43, which is spaced to the right of port 42, communicates with an annular groove 48 formed on the exterior of the sleeve 38. The groove, in turn, communicates with a series of radially extending openings 50 formed in the sleeve and terminating in portion 40a of the bore 40. Port 43 is connected by a passageway 51 formed in the cap which terminates in a cavity 52, shown in FIGS. 6, 8 and 10, and disposed between cavity portion 31a and cavity 37. Cavity 52 and its function will be described more fully hereinafter.

Port 44 is located to the right of port 43, as viewed in FIG. 6, and is aligned with an exterior groove 53 formed in the exterior of sleeve 38. Extending radially inwardly from groove 53 to bore portion 40b are a plurality of symmetrically arranged openings 54. A passageway 55 is formed in the cap and connects the inner end 52b of cavity 52 with port 44. A second passageway 56, see FIG. 7, leads from the groove 53 down wardly to the interior of housing section 21b which is disposed outside of cylinder 22 and, thus, is continuously charged with pressured air, see FIG. 7.

Port 45 to the right of port 44 is in communication with an external groove 57 formed in the exterior of sleeve 38 from which extend radially inwardly a plurality of symmetrically arranged openings 58, which terminate at bore portion 40b. A passageway 59 extends downwardly from port 45 and terminates in the upper portion 31b of cavity 31, see FIG. '7.

Port 46, spaced to the right of port 45, communicates with the right end portion 37a of cavity 37. An elongated passageway 60 connects port 46 to a trigger valve assembly 61 which is mounted on the handle section 21a of the housing 21. The trigger valve assembly will be described more fully hereinafter.

Suitable O-rings 62, see FIG. 10, are carried on the exterior of the sleeve 38 and sealingly engage the surface of cavity 37 and prevent leakage of pressured air longitudinally between the sleeve and cavity surface.

Valve member 41 has a length which is shorter than the length of the bore formed in sleeve 38, thereby enabling the member 41 to move longitudinally within the bore depending upon which of the ports formed in the cavity 37 are charged with pressured air. As seen in FIGS. 6, 8 and 10, valve member 41 is provided with longitudinally spaced shoulders or flanges 63, 64 and 65, each of which is encompassed by an O ring 66, see

FIG. 10. Each ring 66 slidably and sealingly engages the surface of the sleeve 38 defining the bore 40. Because bore portion 40a has a greater diameter than bore portion 40b, shoulder 63 will be larger in diameter than shoulders 64 and 65. Thus, when the poppet valve 25 is in its fully opened position B, the portion 40a of the bore disposed to the left-hand side of shoulder 63 becomes charged with pressured air passing through passageway 47 while simultaneously therewith the cavity portion 37a disposed to the right of the shoulder 65 of the member 41 is exhausted of air thereby causing the member 41 to automatically shift from its left-hand position I, FIG. 6, to its right-hand position II, as seen in FIG. 8. How the portion of the bore disposed at the right of shoulder 65 is exhausted of air will be described more fully hereinafter. When member 41 is in position II, shoulder 65 interrupts communication between ports 45 and 46.

Adjustably mounted within cavity 52 is an elongated plunger 67, see FIGS. 6 and 11, which has an elongated portion 67a which is threaded into the outer portion 52a of the cavity. The cavity outer portion 52a in the illustrated embodiment has a greater diameter than the inner portion 52b, the latter being in communication with passageways 51 and 55.

Plunger end 67a has a portion thereof which is exposed and provided with a suitable slot 67b for receiving the end of a screwdriver or the like so that longitudinal adjustment of the plunger may be readily accomplished. The inner end 67c of the plunger is of reduced diameter and is adapted to be positioned within the portion 52b of cavity 52. An 0 ring 68 encompasses the plunger inner end 670 and is adapted to slidably and sealingly engage the wall defining the reduced end portion 52b of cavity 52. Plunger 67 is provided with an axial bore 70 having one end thereof terminating at the exposed slot 67b and the opposite end terminating at a transverse radially extending port 71 which terminates at the exterior of the plunger adjacent the seal 68 but between said seal and the slot 67b, see FIGS. 6, 8 and 10. When the end 670 of the plunger 67 is positioned so that the O ring seal 68 is located between passageways 51 and 55, the port 71 formed in the plunger will be in communication with passageway 51 and thus exhausted of pressured air.

A nut 72 may be threaded onto the exposed end of the plunger 67 to facilitate locking of the plunger in a predetermined position of adjustment. When the plunger 67 is in the position shown in FIG. 10, the drive piston 23 will make only one complete cycle that is to say, it will move from its fully retracted position, FIG. 5, to a fully extended position, not shown, and then back to its fully retracted position for each manual depression of the trigger lever 61a which comprises a component of the trigger valve 61. On the other hand, when plunger 67 is in the position shown in FIG. 6, the drive piston will automatically continue to cycle, provided the trigger lever 61a is retained in a depressed condition and a conventional safety yoke 73 is in a retracted position by reason of bearing against a surface of the work piece, not shown. The utilization of a safety yoke is well known in the art and is mounted on a nose section 74 which is connected to and depends from the underside of the housing head section 21b.

The operation of the drive piston 23 is determined by poppet valve 25 which in turn is controlled by the trigger valve 61. As seen in FIG. 5, valve 61 includes a sleeve 75 which is disposed within a suitable opening 76 formed in underside of the handle section 21a of the housing. The upper end of the sleeve 75 extends into the hollow interior of the handle section and is provided with an opening 75a which effects communication between the handle section interior charged with pressured airand the interior of the sleeve. Suitable 0 rings 77 encompass the exterior of sleeve 75 and are in sealing contact with the wall defining the opening 76. Intermediate the ends of the sleeve 75 there are provided a plurality of symmetrically arranged openings 78 which are in communication with the lower end 600 of the passageway 60.

Slidably disposed within this sleeve 75 is an elongated valve piece 'which has the upper end 80a thereof engaged by a coil spring 79 causing said piece to be biased in a down (extended) position, as shown in FIG. 5. The upper end 80aof the piece 80 carries an O ring so that when the piece 80 is in its up (retracted) position by reason of the trigger lever 61a being manually depressed, the upper end 80a will be disposed between the upper opening 75a and the openings 78 formed in the sleeve andthus, interrupt communication between said openings. Simultaneously with opening 75a being cut-off from openings 78, the latter are exhausted to the atmosphere along the splined lower portion 80b of the valve piece 80.

When the lever 61a is not depressed, the piece 80 will resume its normal down position, see FIG. 5, whereby the upper end 80a of the valve piece is disposed beneath the openings 78 thereby causing passageway 60 to be charged with the pressured air accumulated within the handle section 21a.

Drive piston 23, in the illustrated embodiment, is of a conventional single spool design; however, if desired a double spool type drive piston may be substituted therefor. If a double spool type drive piston was utilized the cylinder 22 would be of a type shown in US. Pat. No. 3,651,740. Cylinder 22, as shown in FIG. 5, is provided with a first set of openings 81 and a second set of enlarged openings 82, the latter being spaced downwardly from the first set of openings. Both sets of openings communicate with a chamber 83 formed within the interior of the head section 21b of the housing 21. The chamber 83 is separated from the remainder of the housing interior by a partition 21c, see FIG. 5, which is provided with an O ring in sealing engagement with the exterior of cylinder 22.

The location of the first set of openings 81 is such that as the drive piston is about to reach the end of its drive (down) stroke, the openings 81 communicate with the portion of the cylinder interior disposed above the drive piston and, thus, the pressured air within said cylinder interior flows through the openings and into the chamber 83 wherein the pressured air is accumulated. The accumulated air within chamber 83 serves to return the drive piston to its fully retracted position as shown in FIG. 5 once the air above the drive piston has been exhausted.

The lower end of the cylinder 22 is closed off by a replaceable bumper piece 84 which is of resilient material capable of absorbing the impact of the drive piston 23 upon the latter reaching the end of its drive stroke. The bumper piece 84 may be provided with a central opening through which extends a blade 23a carried by the drive piston or, where the central opening is larger than the cross-sectional shape of the blade, a separate seal may be utilized which is positioned between the underside of the bumper piece and the lower end of the housing section and has a central opening which is sized so as to snugly and slidably accommodate the blade.

Once the bumper piece becomes worn or deteriorated, the O-ring carried by the drive piston will become wedged in the large openings 82 and, thus, the pressured air accumulated within chamber 83 will be exhausted to the atmosphere upon the trigger lever 610 being released and valve 25 assuming its down position A. On the other hand, when the bumper piece is operating properly, the piston will rebound slightly closing off openings 81 thereby causing the accumulated pressure air to pass from chamber 83 through openings 82 and, thus, impinging against the underside of the drive piston. Simultaneously, with this occurrence, the poppet valve 25 resumes its normal closed position A whereby the air entrapped above the drive piston will be exhausted through passageways 25c and 35.

While the poppet valve is in its open position B, pressured air is introduced into the upper portion of the cylinder 22 and causes the drive piston to move downwardly. Simultaneously therewith the pressured air is introduced into passageways 25c and 47 thereby impinging upon the left end of member 41 causing same to move to the right as seen in FIG. 8. While member 41 is disposed in such a position, passageways 51, 55 and 59 are charged with pressured air by reason of the fact that passageway 56, which is in communication with said passageways, is always charged with the pressured air accumulated in the hollow handle section 21a, as seen in FIG. 5. Upon passageway 59 being charged with pressured air, the upper part of cavity 31 is also charged with pressured air whereupon the combined force of the pressured air and the biasing spring 32 will cause the poppet valve 25 to return to its closed position A. Upon valve 25 assuming its closed position, the portion of the cylinder above the drive piston is exhausted of pressured air through the bore 25c formed in the valve 25 and the passageway 35 formed in the cap. While the valve 25 is in position A, the upper end of the tubular portion 25a is no longer in sealing engagement with seal piece 36, whereupon the left hand end of the bore 40a is exhausted of pressured air through passageways 47 and 35, and the spool valve 41 once again resumes its position 1, shown in FIG. 6 due to the force of the pressured air which is exerted upon shoulders 63 and 64 of valve 41. As aforementioned, the diameter of shoulder 63 is greater than that of shoulder 64 and thus the force exerted on shoulder 63 would dominate. Once the trigger valve 61 or the safety yoke 73 is released, the pressured air will accumulate in the right end of bore 40b and will cause valve 41 to move to position I, see FIG. 10. The aforedescribed cycle of operation of the poppet valve 25 and spool valve 41 will automatically repeat itself indefinitely, provided the plunger 67 is set in the position shown in FIG. 6; the trigger lever 61a is retained in a manually depressed condition, and the safety yoke 73 carried on the nose section 74 is retained in a retracted position.

If it is desired to limit the operation of the drive piston to one complete cycle of operation that is to say, the piston moves from its fully retracted position, as seen in FIG. 5, to its fully extended position, not shown, and then returns to its fully retracted position, the plunger 67 is manually adjusted so as to assume the position shown in FIG. 10. When the plunger is in such a position, communication between passageways 51 and 55 is blocked and, thus, passageway 51 is always in a state of exhaust and passageway 55 is always charged with pressured air. The net effect of this latter arrangement is that the spool valve 41 will move to the right, see FIG. 8, only as long as trigger lever 61a is depressed and safety yoke 73 is retracted. Once the lever 61a is released or the safety yoke 73 returns to its extended position, passageway 60, port 46 and the right end portion 40b of the bore 40 will become charged with pressured air causing spool valve 41 to return to its normal left position I.

As previously mentioned, the operational speed of the tool is controlled by manually rotating the sleeve 38 relative to the cavity 37. This is accomplished by inserting the tip of a screwdriver or the like within the exposed slot 380 formed at one end of the sleeve. When the sleeve is in the position shown in FIG. 13, the opening 38d formed therein is aligned with port 42; thus, the charging or exhausting of pressured air in bore portion 40a is unobstructed and the tool is operating at maximum speed. When, however, the sleeve assumes the position, shown in FIG. 12, the opening 38d is out of alignment and farthest removed from port 42 and communication between opening 38d and port 42 is by the small clearance maintained between the wall of cavity 37 and the exterior surface of the sleeve.

The cap 26 is of such a design that it is capable of being used on a single actuation tool and will convert same into a single, multi-cycle operating tool. A single actuation tool in this instance is intended to mean one wherein upon the trigger lever thereof being manually depressed, the drive piston will move from its fully retracted position to its fully extended position and remain in the latter position until the trigger lever is released. Furthermore, the single actuation tool must have a removable cap, a poppet valve, a trigger valve, and a piston return spring or a housing chamber in which pressured air will accumulate to effect return of the piston to its fully retracted position.

Thus, it will be noted that a universal type cap has been provided which is of simple, compact and sturdy construction and is capable of being used on either a new or used too] and readily enables the drive piston of said tool to be functional on either a one complete cycle or multi-cycle mode of operation when the trigger valve lever thereof is manually depressed and retained in such depressed condition. Furthermore, the improved cap is capable of withstanding abusive handling and does not require an inordinate amount of servicing in order to maintain the tool in proper working order. Because of the effective utilization of the pressured air to operate the tool with the improved cap mounted thereon, a lesser amount of pressured air is required, thereby resulting in a lower cost of operation.

It is to be understood, of course, that the size and shape of the tool and the removable cap therefor may be varied from that shown without departing from the scope of the invention.

I claim:

1. A pneumatically powered fastener-driving tool comprising a housing having sections thereof charged with pressured air; a cylinder disposed within said housing; a reciprocating drive piston mounted within said cylinder for movement between extended and retracted positions; adjustable first valve means disposed at one end of said cylinder for movement between open and closed positions with respect thereto; manually actuated second valve means mounted on said housing for controlling the movement of said first valve means to said open position whereby said drive piston is exposed to pressured air and moves from said retracted to said extended positions; and a cap removably mounted on said housing adjacent said cylinder one end; said cap including a first cavity in which said first valve means is adjustably mounted, a second cavity spaced from said first cavity, a pneumatically responsive third valve means adjustably mounted within said second cavity, said second cavity being provided with a plurality of longitudinally spaced ports, a first passageway, when said first valve means is in an open position, connecting one of said housing sections charged with pressurized air with a first port, second and third ports being interconnected by a by-passing second passageway, said third port being continuously charged with pressured air, a third passageway connecting a fourth port with a second portion of said first cavity, the first and second portions of said first cavity being continuously separated from one another by said first valve means, a fourth passageway connecting a fifth port with said second valve means, said third valve means when in one position of adjustment effecting interconnection of said fourth and fifth ports through said second cavity whereby said drive piston moves from said retracted position to said extended position, and when in a second position of adjustment, effecting interconnection of said third and fourth ports whereby said drive piston moves from said extended position to said retracted position; and an exhaust passageway connected to said first cavity and communicating with said first passageway when said first valve means is in said closed position with respect to said cylinder one end; said cap including manually adjustable cyclecontrol means disposed within said second passageway and, when in a first position of adjustment, effecting interconnection of said second and third ports and repetitive cycling of said drive piston while said second valve means is manually retained in an actuated condition, and when in a second position of adjustment, interrupting interconnection between said second and third ports whereby said drive piston will make only one complete cycle and return to its original position upon said second valve means being manually actuated and then released.

2. The pneumatically powered fastener-driving tool of claim 1 wherein said third valve means comprises an elongated longitudinally adjustable spool member having a plurality of longitudinally spaced shoulders in sliding sealing engagement with the wall of said second cavity; said spool member when in one position of adjustment having a first shoulder interposed said first and second ports, a second shoulder interposed said second and third ports and a third shoulder interposed said third and fourth ports whereby said fourth and fifth ports are interconnected; said spool member, when in a second position of adjustment, having said first shoulder interposed said first and second ports, said second shoulder interposed said second and third ports, and said third shoulder interposed said fourth and fifth ports.

3. The pneumatically powered fastener-driving tool of claim 1 wherein said cycle-control means includes an elongated plunger mounted for longitudinal adjustment transversely of said second passageway between two predetermined positions; said plunger having an exposed outer end and an inner end, said plunger, when in one of said predetermined positions of adjustment, having said inner end disposed in blocking position within said second passageway between said second and third ports whereby said second port communicates with the exterior of said housing through an outlet formed in said plunger, said outlet having one terminus thereof opening on the exterior of said plunger adjacent to but spaced from the inner end of said plunger and the opposite terminus thereof opening at the exposed exterior of said plunger outer end, and when said plunger is in the second position of adjustment, the inner end of said plunger is in a non-blocking position with respect to said second passageway; said drive piston being capable of only a single cycle of operation when said plunger is in said first predetermined position and being capable of repetitive cycling when said plunger is in said second predetermined position.

4. The pneumatically powered fastener-driving tool of claim 2 wherein the first shoulder of said elongated spool member has a larger diameter than the diameters of the remaining shoulders.

5. In a pneumatically powered fastener-driving tool having a housing with the interior thereof charged with pressured air, a cylinder disposed within the housing, a drive piston mounted within the cylinder for reciprocatory movement between a retracted position and an extended position, an adjustable first valve means disposed atone end of the cylinder for movement between open and closed positions, and manually actuated second valve means mounted on the housing and controlling the movement of the first valve means; a cap removably mountable on the housing adjacent the one end of the cylinder, said cap comprising an adjustably mounted pneumatically responsive first means adapted to cooperate with the first and second valve means to effect at least one complete cycle of movement of the drive piston within the cylinder upon the second valve means being manually actuated, and an adjustably mounted second means selectively adjustable between two predetermined positions; said second means, when in one predetermined position, being adapted to cooperate with said first means and the first and second valve means to effect automatic repetitive cycling movement of the drive piston within the cylinder upon the second valve means being retained in a manually actuated condition; said second means, when in a second predetermined position, being adapted to cooperate with said first means and the first and second valve means to effect only a single complete cycle of movement of the driven piston within the cylinder upon manual actuation of the second valve means.

6. The cap of claim 5 wherein said first means includes an elongated spool member mounted for reciprocatory longitudinal movement within an elongated cavity having the wall thereof provided with a plurality of longitudinally spaced shoulders in sliding sealing contact with the cavity wall, said spool member, when in said one predetermined position, having the shoulders thereof disposed in a first relative position with respect to said ports, and when in said second predetermined position, having the shoulders thereof disposed in a second relative position with respect to said ports.

7. The pneumatically powered fastener-driving tool of claim 1 wherein said cap includes manually adjustspaced openings adapted to communicate with corresponding ports formed in said second cavity; one of said sleeve openings being in substantial alignment with the second cavity first port when said sleeve is disposed in one position of rotational adjustment, whereby said tool is operable at maximum speed and being out of alignment with said first port and in communication therewith by means of a restricted passageway upon said sleeve assuming a second position of rotational adjustment whereby said tool is operable at minimum speed. 

1. A pneumatically powered fastener-driving tool comprising a housing having sections thereof charged with pressured air; a cylinder disposed within said housing; a reciprocating drive piston mounted within said cylinder for movement between extended and retracted positions; adjustable first valve means disposed at one end of said cylinder for movement between open and closed positions with respect thereto; manually actuated second valve means mounted on said housing for controlling the movement of said first valve means to said open position whereby said drive piston is exposed to pressured air and moves from said retracted to said extended positions; and a cap removably mounted on said housing adjacent said cylinder one end; said cap including a first cavity in which said first valve means is adjustably mounted, a second cavity spaced from said first cavity, a pneumatically responsive third valve means adjustably mounted within said second cavity, said second cavity being provided with a plurality of longitudinally spaced ports, a first passageway, when said first valve means is in an open position, connecting one of said housing sections charged with pressurized air with a first port, second and third ports being interconnected by a bypassing second passageway, said third port being continuously charged with pressured air, a third passageway connecting a fourth port with a second portion of said first cavity, the first and second portions of said first cavity being continuously separated from one another by said first valve means, a fourth passageway connecting a fifth port with said second valve means, said third valve means when in one position of adjustment effecting interconnection of said fourth and fifth ports through said second cavity whereby said drive piston moves from said retracted position to said extended position, and when in a second position of adjustment, effecting interconnection of said third and fourth ports whereby said drive piston moves from said extended position to said retracted position; and an exhaust passageway connected to said first cavity and communicating with said first passageway when said first valve means is in said closed position with respect to said cylinder one end; said cap including manually adjustable cycle-control means disposed within said second passageway and, when in a first position of adjustment, effecting interconnection of said second and third ports and repetitive cycling of said drive piston while said second valve means is manually retained in an actuated condition, and when in a second position of adjustment, interrupting interconnection between said second and third ports whereby said drive piston will make only one complete cycle and return to its original position upon said second valve means being manually actuated and then released.
 2. The pneumatically powered fastener-driving tool of claim 1 wherein said third valve means comprises an elongated longitudinally adjustable spool member having a plurality of longitudinally spaced shoulders in sliding sealing engagement with the wall of said second cavity; said spool member when in one position of adjustment having a first shoulder interposed said first and second ports, a second shoulder interposed said second and third ports and a third shoulder interposed said third and fourth ports whereby said fourth and fifth ports are interconnected; said spool member, when in a second position of adjustment, having said first shoulder interposed said first aNd second ports, said second shoulder interposed said second and third ports, and said third shoulder interposed said fourth and fifth ports.
 3. The pneumatically powered fastener-driving tool of claim 1 wherein said cycle-control means includes an elongated plunger mounted for longitudinal adjustment transversely of said second passageway between two predetermined positions; said plunger having an exposed outer end and an inner end, said plunger, when in one of said predetermined positions of adjustment, having said inner end disposed in blocking position within said second passageway between said second and third ports whereby said second port communicates with the exterior of said housing through an outlet formed in said plunger, said outlet having one terminus thereof opening on the exterior of said plunger adjacent to but spaced from the inner end of said plunger and the opposite terminus thereof opening at the exposed exterior of said plunger outer end, and when said plunger is in the second position of adjustment, the inner end of said plunger is in a non-blocking position with respect to said second passageway; said drive piston being capable of only a single cycle of operation when said plunger is in said first predetermined position and being capable of repetitive cycling when said plunger is in said second predetermined position.
 4. The pneumatically powered fastener-driving tool of claim 2 wherein the first shoulder of said elongated spool member has a larger diameter than the diameters of the remaining shoulders.
 5. In a pneumatically powered fastener-driving tool having a housing with the interior thereof charged with pressured air, a cylinder disposed within the housing, a drive piston mounted within the cylinder for reciprocatory movement between a retracted position and an extended position, an adjustable first valve means disposed at one end of the cylinder for movement between open and closed positions, and manually actuated second valve means mounted on the housing and controlling the movement of the first valve means; a cap removably mountable on the housing adjacent the one end of the cylinder, said cap comprising an adjustably mounted pneumatically responsive first means adapted to cooperate with the first and second valve means to effect at least one complete cycle of movement of the drive piston within the cylinder upon the second valve means being manually actuated, and an adjustably mounted second means selectively adjustable between two predetermined positions; said second means, when in one predetermined position, being adapted to cooperate with said first means and the first and second valve means to effect automatic repetitive cycling movement of the drive piston within the cylinder upon the second valve means being retained in a manually actuated condition; said second means, when in a second predetermined position, being adapted to cooperate with said first means and the first and second valve means to effect only a single complete cycle of movement of the driven piston within the cylinder upon manual actuation of the second valve means.
 6. The cap of claim 5 wherein said first means includes an elongated spool member mounted for reciprocatory longitudinal movement within an elongated cavity having the wall thereof provided with a plurality of longitudinally spaced shoulders in sliding sealing contact with the cavity wall, said spool member, when in said one predetermined position, having the shoulders thereof disposed in a first relative position with respect to said ports, and when in said second predetermined position, having the shoulders thereof disposed in a second relative position with respect to said ports.
 7. The pneumatically powered fastener-driving tool of claim 1 wherein said cap includes manually adjustable means for controlling the operational speed of the tool upon said second valve means being actuated.
 8. The pneumatically powered fastener-driving tool of claim 7 wherein said manually adjusted means includes an elongated sleeve rotatably mounted within the second cavity of said cap and being substantially coextensive therewith, said third valve means being adjustably mounted within said sleeve, said sleeve having an exposed closed end provided with means for manually rotating said sleeve relative to said second cavity about the longitudinal axis of said second cavity; said sleeve being provided with a plurality of longitudinally spaced openings adapted to communicate with corresponding ports formed in said second cavity; one of said sleeve openings being in substantial alignment with the second cavity first port when said sleeve is disposed in one position of rotational adjustment, whereby said tool is operable at maximum speed and being out of alignment with said first port and in communication therewith by means of a restricted passageway upon said sleeve assuming a second position of rotational adjustment whereby said tool is operable at minimum speed. 